temptation and just sip your coffee instead. Later that day, you are craving fettuccine alfredo for lunch but you force yourself to order a garden salad with grilled chicken. An hour later, you want to knock off a little early since your boss is out, but you stop yourself and say, “No, I must finish this project.” In each of these instances your hedonic instincts prompt you toward pleasurable types of gratification, while your laudable self-control (or willpower) applies opposing force in an attempt to counteract these urges.
The basic idea behind ego depletion is that resisting temptation takes considerable effort and energy. Think of your willpower as a muscle. When we see fried chicken or a chocolate milkshake, our first reaction is an instinctive “Yum, want!” Then, as we try to overcome the desire, we expend a bit of energy. Each of the decisions we make to avoid temptation takes some degree of effort (like lifting a weight once), and we exhaust our willpower by using it over and over (like lifting a weight over and over). This means that after a long day of saying “no” to various and sundry temptations, our capacity for resisting them diminishes—until at some point we surrender and end up with a belly full of cheese danish, Oreos, french fries, or whatever it is that makes us salivate. This, of course, is a worrisome thought. After all, our days are increasingly full of decisions, along with a never-ending barrage of temptations. If our repeated attempts to control ourselves deplete our ability to do so, is it any wonder that we so often fail? Ego depletion also helps explain why our evenings are particularly filled with failed attempts at self- control—after a long day of working hard to be good, we get tired of it all. And as night falls, we are particularly likely to succumb to our desires (think of late-night snacking as the culmination of a day’s worth of resisting temptation).
WHEN JUDGES GET TIRED
In case you’ve got a parole hearing coming up, make sure it’s first thing in the morning or right after lunchtime. Why? According to a study by Shai Danziger (a professor at Tel Aviv University), Jonathan Levav (a professor at Stanford University), and Liora Avnaim-Pesso (a professor at Ben-Gurion University of the Negev), judges on parole boards tend to grant parole more frequently when they are most refreshed. Investigating a large set of parole rulings in Israel, the researchers found that parole boards were more likely to grant parole during their first cases of the day and just after their lunch breaks. Why? The default decision of parole boards is not to grant parole. But it seems that when the judges felt rejuvenated, which was first thing in the morning or after just having eaten and taken a break, they had an increased ability to override their standard decision, make a more effortful decision, and grant parole more frequently. But over the many difficult decisions of the day, as their cognitive burden was building up, they opted for the simpler, default decision of not granting parole.
I think that PhD students (a slightly different sort of prisoner) instinctively understand this mechanism, which is why they often bring doughnuts, muffins, and cookies to their dissertation proposals and defenses. Based on the results of the parole study, it is likely that their judges are more likely to grant them academic parole and let them start their own independent lives.
Testing the Moral Muscle
In the TV series
Our first experiment included several steps. First, we split our participants into two groups. We asked one group to write a short essay about what they had done the previous day without using the letters “x” and “z.” To get a feeling for this task, try it yourself: In the space below, write a short synopsis of one of your favorite books, but don’t use the letters “x” and “z.” Note: you cannot simply omit the letters from the words—you must use words that do not contain an “x” or “z” (e.g., “bicycle”).
We called this the nondepleting condition because, as you can tell, it’s pretty easy to write an essay without using the letters “x” and “z.”
We asked the other group to do the same thing but told them not to use the letters “a” and “n.” To get a better grasp of how this version of the task is different, try writing a short synopsis of one of your favorite movies while not using any words that contain the letters “a” and “n.”
As you probably discovered from your experience with the second task, trying to tell a story without using “a” and “n” required our storytellers to constantly repress the words that naturally popped into their minds. You can’t write that the characters “went for a walk in the park” or “ran into each other at a restaurant.”
All of those little acts of repression add up to greater depletion.
Once our participants turned in their essays, we asked them to perform a separate task for a different study, which was the main focus of this experiment. The other task was our standard matrix test.
How did things turn out? In the two control conditions, we found that both the depleted and nondepleted folks showed an equal ability to solve the math problems—which means that depletion did not diminish their basic ability to do the math. But in the two shredder conditions (in which they could cheat), things went differently. Those who wrote essays without the letters “x” and “z” and later shredded their answers indulged in a little bit of cheating, claiming to solve about one extra matrix correctly. But the participants in the shredder condition who’d undergone the ordeal of writing essays without the letters “a” and “n” took the proverbial cake: they claimed to have correctly solved about three extra matrices. As it turned out, the more taxing and depleting the task, the more participants cheated.
What do these findings suggest? Generally speaking, if you wear down your willpower, you will have considerably more trouble regulating your desires, and that difficulty can wear down your honesty as well.
Dead Grannies
Over the course of many years of teaching, I’ve noticed that there typically seems to be a rash of deaths among students’ relatives at the end of the semester, and it happens mostly in the week before final exams and before papers are due. In an average semester, about 10 percent of my students come to me asking for an extension because someone has died—usually a grandmother. Of course I find it very sad and am always ready to sympathize with my students and give them more time to complete their assignments. But the question remains: what is it about the weeks before finals that is so dangerous to students’ relatives?
Most professors encounter the same puzzling phenomenon, and I’ll guess that we have come to suspect some kind of causal relationship between exams and sudden deaths among grandmothers. In fact, one intrepid researcher